The purpose of this project is to further define the biochemical basis of amoeboid movement, ingestion, and microbial killing by phagocytic cells. Based on the assumption that contractile proteins and microtubules are the driving force behind ameboid movement, the plan is to isolate contractile proteins from phagocyte cells and tubulin, the major constituent of microtubules, from bovine brain, which protein shares close homology to other cytoplasmic tubulins. Since H2O2 attenuates ingestion by phagocytes, studies will be performed to investigate the effect of H2O2 and other oxygen byproducts on consistency changes of solutions brought about by the interaction of the contractile proteins. Since ascorbic acid has been shown to enhance phagocytic function dependent upon microtubules in the Chediak-Higashi syndrome, the effect of ascorbate on normal phagocytic function related to microtutules such as capping will be determined. Also the effect of ascorbate on enhancing purified tubulin polymerization will be ascertained by monitoring turbidity and viscosity changes of tubulin solutions during warming. Other potential disorders of microtubule function in phagocytes will be examined by inducing alterations of glutathione levels, shown previously to affect tubulin assembly, in selenium deprived rats. BIBLIOGRAPHIC REFERENCES: Boxer LA, Baehner RL and Davis J: The effect of 2-deoxyglucose on guinea pig polymorphonuclear leukocyte phagocytosis. J Cellular Physiol 91:89-102, 1977. Boxer LA, Rister M, Allen JM and Baehner RL: Improvement of Chediak-Higashi leukocyte function by cyclic guanosine monophosphate. Blood 49:9-17, 1977.